1. Field of the Invention
The present invention relates to a method and apparatus of automatically controlling a sailboat.
2. Description of the Prior Art
Recently, some large-sized ships such as bulk carriers tankers are being provided with sails to save energy. In such large-size ships, a computer is used to control the sails for economical optimization. Sails used in the large-sized ships are substantially made of metals or plastics. Manufacturing cost therefor is huge. Mechanisms for operating the sails are very complicated.
Some fishing boats also begin to use a sailing apparatus having a relatively simplified structure in which when push buttons are manually depressed in the bridge of a fishing boat, sails including jib and main sails can remotely be controlled to hoist or haul down the sails. However, such a sailing apparatus cannot delicately adjust the angle or curvature in the sails depending on the direction and velocity of the wind.
To utilize the wind force with maximum efficiency, the angle and curvature in the sails must be adjusted to generate maximum lift. It is therefore desirable to spread each of the sails on a line bisecting an angle included between the advancing direction of the ship and the apparent wind and also to adjust the curvature of the sail up to a limit to which the sail does not shiver. In the prior art, such controls completely depends on the experiences and feels of a skilled operator. It is also difficult for him to continue the controlling operation throughout the sailing.
The term "angle of sail" used herein means the angle of a sail relative to the fore-and-aft axis of a ship's hull.
The term "angle of boom" used herein means the angle of a boom relative to the fore-and-aft axis of the hull.
The term "apparent wind" used herein means a wind against a ship running on water.